1. Field of the Invention
The present invention relates to a magnetooptical recording apparatus for recording information by irradiating a light beam and applying a modulated magnetic field onto a magnetooptical recording medium.
2. Related Background Art
As a conventional method of recording information on an overwrite capable magnetooptical recording medium, an optical modulation overwrite method for performing an overwrite operation by changing laser beam power using an exchange-coupled multilayered film, or a magnetic field modulation recording method for recording information by applying an external magnetic field modulated according to recording information while irradiating a laser beam onto a magnetooptical recording medium, is known.
However, although the above-mentioned optical modulation overwrite method is advantageous in terms of high-speed recording since a light beam is modulated, jitter of a reproduction signal upon execution of pit edge recording is impaired due to a change in size of a pit to be recorded due to a high light beam intensity required for recording, a variation in recording sensitivity of a magnetooptical recording medium, or a change in environmental temperature, and it is difficult to increase the recording density.
In contrast to this, since the magnetic field modulation recording method suffers from less pit edge shift due to a change in intensity of a laser beam, it is suitable for a pit edge recording method for increasing the recording density. However, this method is disadvantageous in terms of high-speed recording since a strong magnetic field to be applied must be modulated at high speed in the recording mode while overcoming magnetic fields generated by the magnetooptical recording medium itself and the magnetooptical recording apparatus, as well. The magnetic field generated by the magnetooptical recording medium itself is a self leakage magnetic field applied from a surrounding portion which has not lost magnetization to a portion near the center of the light beam, which portion has lost magnetization when a recording light beam is irradiated from an optical pickup to a magnetooptical recording layer. The magnetic field generated by the magnetooptical recording apparatus includes a magnetic field generated by an actuator in the optical pickup, a magnetic field generated by a motor for performing a seek operation, a magnetic field generated by a clamp magnet for clamping a magnetooptical disk in the magnetooptical recording apparatus, leakage magnetic fields generated by motors arranged in the magnetooptical recording apparatus to perform various operations such as a loading operation of the magnetooptical recording medium, and the like.